A hitherto-disclosed, related art gas cutoff apparatus of this type has a flow measurement unit that outputs a flow signal conforming to the quantity of gas passed; an individual appliance estimation unit that estimates an increase or decrease in the number of individual appliances in operation when the flow signal is increased or decreased and that outputs an estimated individual computed flow quantity of an individual appliance caused the increase or decrease and a time during which the appliance has been used; an individual flow registration unit that previously registers the flow quantity of an individual appliance to be used and that outputs a registered individual flow quantity and a time during which the appliance has been used; an individual flow memory unit that stores the registered individual flow quantity; an abnormal flow determination section that outputs an individual abnormality signal when the estimated individual computed flow quantity of the appliance caused the increase or decrease is not included in the registered individual flow quantity stored in the individual flow memory unit and when a continual operating time of the appliance caused the increase or decrease is a first predetermined time or more; an alarm unit that reports an abnormality in the gas flow quantity by issuing an alarm upon receipt of the individual abnormality signal or a cutoff unit that cuts off a gas passageway upon receipt of the individual abnormality signal; and a regular individual flow registration unit that registers the estimated individual computed flow quantity generated by the individual flow estimation unit in the individual flow memory unit when the estimated, individual, computed flow quantity of the appliance generated by the individual appliance estimation unit is not included in the registered individual flow quantity stored in the individual flow memory unit and when an operating time of the appliance determined by the individual appliance estimation unit is longer than a second predetermined time and shorter than the first predetermined time (see; for instance, Patent Document 1).
The gas cutoff apparatus of Patent Document 1 is briefly described by reference to FIG. 17, and reference numeral 101 designates a flow measurement unit; namely, a flow sensor attached to a gas meter. Reference numeral 102 designates an individual appliance estimation unit and computes a flow signal “s” of a flow sensor 1 as an average flow for a given measurement period (30 seconds); estimates an increase or decrease in individual flow in use from an increase or decrease in average flow; and outputs an estimated individual computed flow Q of the appliance caused the increase or decrease and a time during which the appliance has been used. When the average flow quantity has increased, the individual appliance estimation unit 102 determines that a gas appliance conforming to the increase is used. In contrast, when the average flow quantity has decreased, the individual appliance estimation unit determines that the gas appliance conforming to the decrease is stopped and estimates an individual appliance in use. Reference numeral 103 designates an individual flow registration unit that is a setting device for previously inputting the flow quantity (Qi) of an individual appliance used in a household. Reference numeral 104 designates an individual flow memory unit that stores the flow quantity (Qi) of an individual appliance of the individual flow registration unit 103 and flow quantities in a regular individual flow registration unit 107 in sequence of Q1, Q2, Q3, . . . , Qn. Reference numeral 105 designates an abnormal flow determination section that outputs an individual abnormality signal E when the estimated individual flow quantity Q output from the individual appliance estimation unit 102 is not included in flow quantities [Q1, Q2, Q3, . . . , Qn] of the individual flow memory unit 104 and when the estimated individual flow quantity Q continues for a first predetermined time (10 minutes) or more. Reference numeral 106 designates an alarm unit or a cutoff unit equipped with an LCD or LED that reports an alarm upon receipt of the individual abnormality signal E or a cutoff valve that cuts off a gas passageway. Reference numeral 107 designates a regular individual flow registration unit that outputs the estimated individual flow quantity Q to the individual flow memory unit 104 when the estimated individual flow quantity Q output from the individual flow estimation unit 102 continues for period ranging from a second predetermined time (three minutes) to the first predetermined time (10 minutes).
Operation of the related art configuration will now be described. An average flow quantity is computed from a flow signal of the flow measurement unit 101. A flow change between the average flow quantity and the last average flow quantity but one is computed, to thus determine whether the change is an increase or a decrease. The estimated individual computed flow quantity Q is determined by means of corresponding processing. It is determined whether or not an estimated individual computed flow quantity Q newly determined as a result of increase processing or decrease processing is included in the individual flow memory unit 104 and whether or not the estimated individual appliance has been used for the first predetermined time (10 minutes). When the estimated individual computed flow is not included and when the estimated individual appliance is used for 10 minutes or more, the alarm unit or cutoff unit 106 is activated. When the estimated individual computed flow is not included or when the estimated individual appliance is not used for 10 minutes or more, it is determined whether or the flow quantity is an unregistered flow quantity; whether the estimated individual appliance is used for three minutes or more; and whether the estimated individual appliance is used for 10 minutes or less. When all of these conditions are satisfied, the regular individual flow registration unit 107 performs processing for registering the estimated individual appliance in the individual flow memory unit 104.
Provided that an increase Qt (e.g., Q2+Q3) has arisen in an average flow quantity as a result of simultaneous use of a plurality of appliances and that the appliances have been used for; for instance, seven minutes; namely, that the average flow quantity has decreased after elapse of seven minutes, the individual appliance estimation unit 102 outputs the estimated individual flow quantity Qt. When the time during which the appliances are used ranges from three minutes to 10 minutes, the regular individual flow registration unit 107 registers the estimated individual flow quantity Qt in the individual flow memory unit 104. Since the flow quantity of the appliances is registered in the individual flow memory unit 104, gas will not be cut off even when a similar flow quantity appears for 10 minutes or more from then on. Specifically, it is possible to diminish occurrence of erroneous cutoff of gas, which would otherwise be caused by gas appliances that are simultaneously started in many cases. Moreover, when a new individual flow quantity Qk (continued for a period ranging from three minutes to 10 minutes) is caused by a replacement appliance, the individual appliance estimation unit 102 outputs the estimated individual flow quantity Qk. When the replacement appliance is used for a period ranging from three minutes to 10 minutes, the regular individual flow registration unit 107 registers the estimated individual flow quantity Qk in the individual flow memory unit 104.
Since the flow quantity of the replacement appliance is registered in the individual flow memory unit 104, gas is not cut off even when the flow quantity has appeared for 10 minutes or more. Occurrence of an accident, which would otherwise be caused by an escape of gas attributable to a flow other than the flow quantities of the individual appliances, can be prevented by storing the individual appliances used in each household in advance. Thus, it is possible to prevent occurrence of erroneous cutoff of gas, which would otherwise be caused by simultaneous activation of appliances, use of a replacement appliance, or the like.
Patent Document 1: JP-A-7-44239